4O LESSONS ON REFRIGERATION AND AIR CONDITIONING FROM IIT KHARAGPUR. USEFUL TRAINING MATERIAL FOR MECHANICAL ENGINEERING STUDENTS COLLEGE, OR AS REFERENCE FOR ENGINEER

History Of Refrigeration......Page 7
Introduction......Page 8
Natural Refrigeration......Page 9
Vapour Compression Refrigeration Systems:......Page 11
Vapour Absorption Refrigeration Systems:......Page 17
Gas Cycle Refrigeration......Page 20
Steam Jet Refrigeration System......Page 21
Thermoelectric Refrigeration Systems......Page 22
Vortex tube systems......Page 23
Summary......Page 25
History Of Refrigeration – Development Of Refrigerants And Compressors......Page 26
Introduction......Page 27
Refrigerant development – a brief history......Page 28
Compressor development – a brief history......Page 34
Conclusions......Page 43
Applications Of Refrigeration & Air Conditioning......Page 44
Introduction......Page 45
Application of refrigeration in Food processing, preservation and distribution......Page 46
Applications of refrigeration in chemical and process industries......Page 53
Special applications of refrigeration......Page 54
Application of air conditioning:......Page 57
Conclusions......Page 62
Review of fundamental principles – Thermodynamics : Part I......Page 64
Introduction......Page 65
Definitions......Page 66
Fundamental laws of Thermodynamics......Page 68
First law of thermodynamics for a closed system:......Page 69
First law of thermodynamics for open system:......Page 70
Questions:......Page 76
Review of fundamental principles – Thermodynamics : Part II......Page 78
Evaluation of thermodynamic properties......Page 79
Properties Of Pure Substance......Page 81
Thermodynamic processes......Page 87
Review of fundamentals: Fluid flow......Page 93
Fluid flow......Page 94
Conservation of mass:......Page 95
Conservation of momentum:......Page 96
Bernoulli’s equation:......Page 97
Pressure loss during fluid flow:......Page 99
Questions:......Page 101
Review of fundamentals: Heat and Mass transfer......Page 104
Introduction......Page 105
Conduction heat transfer:......Page 106
Radiation heat transfer:......Page 109
Convection Heat Transfer:......Page 110
Convective mass transfer:......Page 117
Analogy between heat, mass and momentum transfer......Page 118
Multimode heat transfer......Page 119
Heat exchangers:......Page 121
Questions:......Page 122
Methods of producing Low Temperatures......Page 124
Sensible cooling by cold medium......Page 125
Phase change processes......Page 126
Expansion of Liquids......Page 127
Expansion of gases......Page 129
Thermoelectric Refrigeration......Page 132
Adiabatic demagnetization......Page 135
Questions:......Page 136
Air cycle refrigeration systems......Page 138
Air Standard Cycle analysis......Page 139
Reversed Carnot cycle employing a gas......Page 140
Ideal reverse Brayton cycle......Page 142
Aircraft cooling systems......Page 147
Simple aircraft refrigeration cycle:......Page 148
Bootstrap system:......Page 149
Questions:......Page 151
Vapour Compression Refrigeration Systems......Page 153
Vapour Compression Refrigeration Systems......Page 154
The Carnot refrigeration cycle......Page 155
Standard Vapour Compression Refrigeration System (VCRS)......Page 161
Vapour Compression Refrigeration Systems:Performance Aspects And Cycle Modifications......Page 171
Performance of SSS cycle......Page 172
Modifications to SSS cycle......Page 175
Effect of superheat on system COP......Page 181
Complete vapour compression refrigeration systems......Page 185
Questions:......Page 186
Comments......Page 192
Multi-Stage Vapour Compression Refrigeration Systems......Page 193
Introduction......Page 194
Flash gas removal using flash tank......Page 197
Intercooling in multi-stage compression......Page 198
Multi-stage system with flash gas removal and intercooling......Page 201
Use of flash tank for flash gas removal......Page 205
Use of flash tank for intercooling only......Page 206
Questions:......Page 208
Multi-Evaporator And Cascade Systems......Page 213
Introduction......Page 214
Individual evaporators and a single compressor with a pressure-reducing valve......Page 215
Multi-evaporator system with multi-compression, intercooling and flash gas removal......Page 222
Limitations of multi-stage systems......Page 224
Cascade Systems......Page 226
Questions......Page 229
Comments:......Page 237
Vapour Absorption Refrigeration Systems......Page 238
Introduction......Page 239
Basic principle......Page 240
Maximum COP of ideal absorption refrigeration system......Page 244
Ideal, homogeneous binary mixtures......Page 247
Real mixtures......Page 248
Basic Vapour Absorption Refrigeration System......Page 250
Refrigerant-absorbent combinations for VARS......Page 251
Questions:......Page 252
Vapour Absorption Refrigeration Systems Based On Water-Lithium Bromide Pair......Page 258
Introduction......Page 259
Vapour pressure of water-lithium bromide solutions......Page 260
Enthalpy of water-lithium bromide solutions......Page 262
Enthalpy values for pure water (liquid and superheated vapour)......Page 263
Steady flow analysis of Water-Lithium Bromide Systems......Page 264
Commercial systems......Page 268
Capacity control......Page 273
Questions:......Page 274
Vapour Absorption Refrigeration Systems Based On Ammonia-Water Pair......Page 279
Introduction......Page 280
Vapour pressure of ammonia-water solutions......Page 281
Composition of ammonia-water vapour......Page 282
Bubble point and dew point for ammonia-water mixtures......Page 283
Enthalpy of ammonia-water mixtures......Page 286
The complete enthalpy-composition diagram for ammonia-water mixtures:......Page 287
Questions and Answers:......Page 297
Vapour Absorption Refrigeration Systems Based On Ammonia-Water Pair......Page 301
Introduction......Page 302
Working principle......Page 303
Principle of rectification column and dephlegmator......Page 304
Steady-flow analysis of the system......Page 306
Pumpless vapour absorption refrigeration systems......Page 309
17.6: Solar energy driven sorption systems......Page 312
Comparison between compression and absorption refrigeration systems......Page 313
Questions and answers:......Page 314
Comments:......Page 316
Refrigeration System Components: Compressors......Page 317
Introduction......Page 318
Classification of compressors......Page 319
Reciprocating compressors......Page 321
Performance of reciprocating compressors......Page 322
Questions and answers:......Page 332
Performance Of Reciprocating Compressors......Page 337
The specific objectives......Page 338
Ideal compressor with clearance:......Page 339
Actual compression process......Page 348
Capacity control of reciprocating compressors:......Page 352
Compressor lubrication:......Page 354
Rotary, Positive Displacement Type Compressors......Page 361
Rolling piston (fixed vane) type compressors:......Page 362
Multiple vane type compressors:......Page 364
Characteristics of rotary, vane type compressors:......Page 365
Rotary, screw compressors:......Page 366
Scroll compressors:......Page 370
Centrifugal Compressors......Page 376
Introduction......Page 377
Analysis of centrifugal compressors:......Page 380
Refrigerant capacity of centrifugal compressors:......Page 388
Capacity control:......Page 390
Performance......Page 391
Questions & answers:......Page 397
Condensers & Evaporators......Page 402
Introduction:......Page 403
Condensers......Page 404
Air-cooled condensers:......Page 405
Water Cooled Condensers:......Page 408
Evaporative condensers:......Page 410
Air cooled vs water cooled condensers:......Page 412
Analysis of condensers:......Page 413
Condenser Heat Rejection Ratio (HRR):......Page 414
Mean temperature difference:......Page 415
Overall heat transfer coefficient:......Page 416
Heat transfer areas in finned tube condensers:......Page 419
Estimation of heat transfer coefficients:......Page 421
Effect of air and non-condensables:......Page 428
Optimum condenser pressure for lowest running cost......Page 429
Questions & answers:......Page 430
Condensers & Evaporators......Page 439
Natural and Forced Convection Type......Page 440
Natural Convection type evaporator coils......Page 441
Flooded Evaporator......Page 442
Flooded Type Shell-and-Tube Evaporator......Page 444
Shell-and-Coil type evaporator......Page 445
Double pipe type evaporator......Page 446
Baudelot type evaporators......Page 447
Direct expansion fin-and-tube type......Page 448
Plate Surface Evaporators......Page 449
Plate type evaporators:......Page 451
Thermal design of evaporators:......Page 452
Wilson’s plot:......Page 459
Questions and answers:......Page 461
Expansion Devices......Page 465
Introduction......Page 466
Capillary Tube......Page 467
Balance Point of Compressor and Capillary Tube......Page 468
Effect Of load variation......Page 469
Selection of Capillary Tube......Page 471
Automatic Expansion Valve (AEV)......Page 482
Effect of Load Variation......Page 485
Flow Rate through orifice......Page 486
Thermostatic Expansion Valve (TEV)......Page 489
TEV with cross charge......Page 491
TEV with External Pressure Equalizer......Page 493
Fade-out point and pressure limiting characteristics of TEV:......Page 494
Float type expansion valves:......Page 496
Low-side float valves:......Page 497
Electronic Type Expansion Valve......Page 498
Practical problems in operation of Expansion valves......Page 499
Questions and answers:......Page 500
Analysis Of Complete Vapour Compression Refrigeration Systems......Page 504
The specific objectives......Page 505
Introduction......Page 506
Reciprocating compressor performance characteristics:......Page 507
25.3. Condenser performance characteristics:......Page 509
Evaporator Performance......Page 513
Condensing unit:......Page 515
Performance of complete system - condensing unit and evaporator:......Page 517
Effect of expansion valve:......Page 519
Conclusion......Page 520
Refrigerants......Page 523
Primary and secondary refrigerants......Page 524
Thermodynamic and thermo-physical properties......Page 525
Environmental and safety properties......Page 527
Designation of refrigerants......Page 528
Comparison between different refrigerants......Page 531
Questions and answers......Page 534
Psychrometry......Page 537
Introduction......Page 538
Methods for estimating properties of moist air......Page 540
Important psychrometric properties......Page 541
Measurement of psychrometric properties......Page 544
Adiabatic saturation and thermodynamic wet bulb temperature......Page 545
Wet-Bulb Thermometer......Page 548
Psychrometer......Page 549
Questions and answers......Page 550
Psychrometric Processes......Page 553
Important psychrometric processes:......Page 554
Air Washers:......Page 563
Enthalpy potential:......Page 565
Questions and answers:......Page 566
Inside And Outside Design Conditions......Page 572
The specific objectives......Page 573
Introduction......Page 574
Thermal comfort:......Page 575
Heat balance equation for a human being:......Page 576
Indices for thermal comfort......Page 581
Predicted Mean Vote (PMV) and Percent People Dissatisfied (PPD):......Page 584
Outdoor design conditions for summer:......Page 586
Outdoor design conditions for winter:......Page 587
Questions and answers:......Page 588
Psychrometry Of Air Conditioning Systems......Page 591
Introduction......Page 592
Simple system with 100 % re-circulated air:......Page 593
System with outdoor air for ventilation:......Page 595
High latent cooling load applications (low RSHF):......Page 599
Guidelines for selection of supply state and cooling coil:......Page 601
Questions and answers:......Page 602
Comments......Page 604
Evaporative, Winter And All Year Air Conditioning Systems......Page 608
Introduction to evaporative air conditioning systems:......Page 609
Direct evaporative cooling systems:......Page 610
Indirect evaporative cooling system:......Page 612
Multi-stage evaporative cooling system......Page 613
Advantages and disadvantages of evaporative cooling systems......Page 614
Applicability of evaporative cooling systems......Page 615
Winter Air Conditioning Systems......Page 616
All year (complete) air conditioning systems......Page 620
Questions and answers......Page 621
Cooling And Heating Load Calculations- Estimation Of Solar Radiation......Page 626
Introduction......Page 627
Solar radiation......Page 628
Total solar irradiation......Page 629
Solar geometry:......Page 631
Derived solar angles:......Page 634
Reflected, short-wave (solar) radiation, Ir......Page 639
Cooling And Heating Load Calculations-Solar Radiation Through Fenestration- Ventilation And Infiltration......Page 645
Solar radiation through fenestration......Page 646
Estimation of solar radiation through fenestration......Page 647
Effect of external shading......Page 650
Ventilation for Indoor Air Quality (IAQ)......Page 653
Infiltration......Page 654
Heating and cooling loads due to ventilation and infiltration......Page 655
Questions & answers......Page 656
Cooling And Heating Load Calculations- Heat Transfer Through Buildings - Fabric Heat Gain/Loss......Page 660
Introduction......Page 661
One-dimensional, steady state heat transfer through buildings......Page 662
Homogeneous wall......Page 663
Non-homogeneous walls:......Page 666
Air spaces:......Page 667
Unsteady heat transfer through opaque walls and roofs......Page 669
One-dimensional, unsteady heat transfer through building walls and roof......Page 670
Analytical solution......Page 672
Semi-empirical methods......Page 675
Cooling And Heating Load Calculations- Estimation Of Required Cooling/Heating Capacity......Page 688
Introduction......Page 689
Heating versus cooling load calculations......Page 690
Methods of estimating cooling and heating loads......Page 691
Cooling load calculations......Page 693
Estimation of the cooling capacity of the system......Page 701
Heating load calculations......Page 703
Questions and answers......Page 704
Selection Of Air Conditioning Systems......Page 709
The specific objectives......Page 710
Selection criteria for air conditioning systems......Page 711
All air systems......Page 712
Single duct, constant volume, single zone systems......Page 713
Single duct, constant volume, multiple zone systems......Page 714
Single duct, variable air volume (VAV) systems......Page 716
Dual duct, constant volume systems......Page 717
Advantages of all air systems......Page 718
All water systems......Page 719
Applications of all water systems......Page 722
Air-water systems......Page 723
Disadvantages of air-water systems......Page 724
Unitary refrigerant based systems......Page 725
Disadvantages of unitary refrigerant based systems......Page 727
Questions and answers......Page 728
Transmission Of Air In Air Conditioning Ducts......Page 734
Introduction:......Page 735
Flow of air through ducts:......Page 736
Estimation of pressure loss in ducts......Page 737
Dynamic losses in ducts......Page 740
Questions and answers......Page 747
Design Of Air Conditioning Ducts......Page 752
The specific objectives......Page 753
General rules for duct design......Page 754
Commonly used duct design methods......Page 755
Performance of duct systems:......Page 761
System balancing and optimization......Page 762
Fans......Page 763
Questions and answers......Page 765
Space Air Distribution......Page 772
Introduction......Page 773
Design of air distribution systems......Page 775
Behaviour of free-stream jet:......Page 777
Circular jets:......Page 779
Rectangular jets:......Page 780
Types of air distribution devices......Page 781
Airflow patterns inside conditioned space......Page 785
Cold air distribution......Page 788
Spot cooling/heating......Page 789
Selection of supply air outlets......Page 791
Questions and answers......Page 792
Ventilation For Cooling......Page 797
Introduction......Page 798
Natural versus mechanical ventilation......Page 799
Natural ventilation......Page 800
Forced ventilation using electric fans......Page 803
Interior air movement......Page 804
Questions and answers......Page 806